“Invisiline” ventilation diffusers -diffusers are made from sections molded in a customized matrix,-2-millimeter-thick powder-coated aluminum.- We have done a big job doing all the tests that we could do to provide the best comfort in terms of noise performance. As long as our recommendations are followed, diffusers perform in an absolutely noiseless manner.The product has an aesthetic look - none of its part are exposed (bolts, nozzles, air ducts – you can not see them). All you can see is a neat line in a wall.